This invention relates to a novel form of intra-oral anchorage, for use in oral surgical procedures.
Intra-oral anchorage refers to a stable point within the mouth, usually a tooth, such that traction may be applied to a less fixed or a moveable structure. Alternatively, two or more anchorage points may be used so that teeth may be held firmly together such that a fracture site nay be aligned and/or that some other surgical procedure may be performed which would necessitate the occlusion being consistent throughout and after the procedure.
This intra-oral anchorage is usually achieved by use of metal wires twisted tightly around the teeth (see FIG. 1A). Additionally, metal bars (arch bars) may be used to create multiple hooks as easy anchorage for traction or fixation (see FIGS. 1B and 1C). Once an anchorage point has been established, traction is usually achieved by means of elastic bands while fixation is by use of more metal wires.
This system of wiring is time consuming and requires skill, dexterity and training. It is so uncomfortable for the patient that it is almost invariably done during a general anaesthesia. The removal of the wire several weeks later is usually under local anaesthesia and is generally distressing and destructive of delicate gingival (gum) structures.
As result of the wire cutting, there are many sharp ends of wire which present hazards to the patient, operator and his assistant, as gloves and skin are often punctured by the wire. This results in a risk of transmission of blood borne infections particularly hepatitis and the AIDS virus which is a well known risk associated with current techniques.
Additionally, wire work hardens and fractures in placement and often stretches with functional load requiring readjustment.
Accordingly, the present invention provides anchorage for use in the treatment of oral fractures comprising a flexible belt of a dimension to extend around and between the teeth of a patient, the belt having locking means fixed thereon to receive a free end portion of the belt and lock said portion against retraction therefrom.
Preferably, the lock means is attached at one end to the belt, and may be generally in the form of a buckle.
Preferably, the locking means is in the form of a head having an aperture therethrough for receiving the end portion of the belt.
Preferably also the head has a one-way lock mechanism to allow advancement, but resist retraction of the belt in the aperture.
The belt may comprise two sections, a first section including the free end of the belt and typically being curved; and a second section between the first section and the locking means.
The second section is preferably profiled to co-operate and lockingly engage with the locking head.
Preferably, the first section has a smooth surface to facilitate passing the belt through inter-dental spaces.
The locking head may have on its outer face means for retaining a fixing member, for example an elastic band, a plastic tie, a wire or a bar, for inter-connecting and fixing to other locking heads.
Advantageously, there are no sharp edges on the anchorage which may be hazardous to the patient or the operator.
The locking means may comprise a plurality of inclined teeth on both the second section of the belt and an inner face of the locking head whereby the teeth co-operate such that the belt can only pass through the aperture in one direction.
The locking means may include an external plate to ensure a coherent fitting of the anchorage to a tooth; the plate may be concave, although it can be varied to suit any given tooth.
In use, where more than one anchorage is used, traction may be applied between the anchorages by wrapping elastic bands or other suitable means around retaining means such that the teeth or fracture points may be drawn into proper alignment and held in place.
The belt is typically between 10 and 14 centimeters in length and around 0.6 to 1.0 millimeters in width.
Said first section of the belt may be typically 1.5 to 3 centimeters long.
The locking head is preferably approximately 7 to 11 millimeters long and approximately 3 to 5 millimeters in width.
Further according to the invention there is provided a method of treating facial or law fractures or facilitating facial or jaw bone surgery, comprising extending a flexible belt around one or more of a patient""s teeth, passing one end portion of the belt through locking means carried on the belt and tensioning the belt around the teeth by drawing it through the locking means, said locking means preventing retraction of the belt therefrom.
The belt is preferably of plastics material.
More preferably the belt is of Nylon having a tensile yield strength of between 50 to 80 MN/m2 and a Rockwell hardness of between 100-140.
Optionally the belt, is of polyketone, having a tensile yield strength of between 50 to 80 MN/m2 and a Rockwell hardness of between 100-140.
Optionally a portion of the belt, especially the first section of the belt may be of steel, having a tensile yield strength of between 175 to 2000 MN/m2 and a modulus of elasticity of between 175 to 230 GN/m2.
The plastic xe2x80x98bucklexe2x80x99 preferably faces outwards from the face of the tooth and incorporates a hook and location point for an arch bar. The entire device can be produced with no sharp edges and may have minor modifications of shape to facilitate placement.